Biopsy has grown to be one of the crucial tools in medicine to determine tissue diagnosis. Due to the large overlap between the representation of diseases on a clinical and radiological level a tissue sample is needed to be investigated pathological to determine appropriate treatment. To perform a targeted biopsy, mostly image guidance is used. In this method, an image modality, mostly ultrasound or CT, is used to track the biopsy needle and the target lesion. However, these modalities come with several limitations.
The use of MRI can overcome these limitations, MRI offers high soft tissue contrast and detail levels over depth combined with options to distinguish between characteristics of pathologies like T1, T2 weighting, perfusion and flow. For abdominal biopsies these advantages can be crucial for reliable clinical outcomes. MRI-guided biopsies are already being performed but large-scale acceptance is hampered by the inaccessibility of the patient due to the narrow design of most conventional MRI systems. Nowadays the patient is moved multiple times in and outwards of the MRI system to manually adjust the biopsy needle in small steps towards the target lesion, the target lesion also moves under effects as pressure given by the needle, breathing or anatomical deformation. The needle placement process is very time-consuming and inefficient.
This master's assignment focuses on the realisation of an in-bare MR Safe robot for biopsy needle positioning with moving abdominal target lesions. This robot should make it possible to guide the needle to the right position without the need of moving the patient relative to the MR scanner and making it possible to adjust the injection path direction by tracking the movement of target lesion and using the entree points as hinge point.
The realisation of the project can be subdivided into the following phases:
- A literature review into existing MRI-safe and conditional robots and designs.
- A realisation phase where the MRI-safe robot is designed and produced.
- A control engineering phase where inverse kinematics are used for a control algorithm.
- An MRI implementation phase where the robot is implemented in the MRI situation and position-controlled by MRI data.
- A displacement tracking phase where the accuracy of injection path adjustment is measured.
The end product of this Master's assignment will be a prototype of an MRI-safe biopsy robot for the abdomen able to guide a needle towards a moved target, and a research paper.